The present invention relates to improvements in an open type refrigerated showcase.
Heretofore, in a refrigerated showcase of the open type, invasion of great amounts of ambient air into the showcase can be a problem, and therefore, a method for minimizing entry of ambient air (b) into the showcase has been employed, in which the lower the temperature in the showcase is, the more layers of air curtains consisting of cold air (a) circulating across a front opening (1) of a refrigerated showcase (A) and along a bottom wall (2), rear wall (3) and top wall (4) thereof are provided, such as a single layer, two layers and three layers, as shown in FIGS. 1, 2 and 3, respectively.
However, in such a prior art structure, in the upper portion of the front opening (1) the ambient air (b) is drawn towards the inside of the showcase so as to collide with shelves (5) resulting in vortexes, the vortexes causing the ambient air (b) to be sucked into the showcase resulting in a lower cooling efficiency.
In order to prevent the above-described invasion of ambient air into the refrigerated showcase, it is necessary to make a layer of cold air extend vertically from an ejection port along the upper edge of the front opening (1) to a suction port along the lower edge thereof by elongating a rectified flow of an air curtain.
However, for the purpose of providing a rectified flow of cold air, it becomes an essential condition to afford an airflow velocity and a directionality to the cold air. If the flow velocity of cold air is increased more than necessary, then the cold air will flow out of the refrigerated showcase, and hence the cooling capability of the showcase will be lowered. Therefore, rectification of a flow at an ejection port becomes the most important necessary condition.
In order to effectively achieve the above-described rectification of a flow of cold air, it is effective to elongate the length of an ejection port as much as possible. However, in view of the structure of a conventional refrigerated showcase, it is impossible to elongate the ejection port to the extent necessary. The present invention has been proposed under the above-mentioned background of the art.